Several methods for joining a wireless network already exist. The basic method is the direct sharing of the WiFi™ key. This method has drawbacks: it is complicated and error prone. Moreover it reveals the WiFi™ key. Having those drawbacks in mind, the WiFi™ alliance promoted WiFi™ Protected Setup (WPS) procedures. This is a set of methods that ease the process of entering a WiFi™ network. In one method called the WPS Push Button Configuration (PBC) method, the user presses two buttons, one on the entering (enrollee) device and one on the access point (AP). This method takes time because of a two minute temporization time period. If this temporization is not implemented, the method is known to be vulnerable. Also, an unintended device could join the network if it is in range. It is well known that service set identifiers SSIDs of AP services may be hidden and not transmitted during normal WLAN operation in order to hide such SSIDs from detection and hacking. However, it is a generally accepted practice to transmit all AP SSID information during a WPS PBC procedure. This is performed so that all of the possible SSIDs of an access point are available for a joining or enrolling station STA to access. But, there are risks for the access point network and the remote station in a WPC PBC process. For example, the STA can mistakenly pair with a wrong SSID resulting in the STA not receiving the AP services it desires. An incorrect pairing of an AP and STA could provide connection to an SSID service that is not authorized for the particular STA. An incorrect pairing may simply not allow proper data exchange because of incompatibilities between different AP and STA capabilities. Service failure, interruption of service, and security breaches may result from incorrect pairings. Also, the STA could pair with the wrong AP resulting in a security threat or operation difficulty.
Solutions to this incorrect pairing problem include transmitting all of the SSIDs during a WPC PBS setup but requiring the STAs to transmit a customer identifier string during the WPS set up so that the AP can recognize and pair only with authorized STAs. This pairing protection scheme PPS insures that unauthorized STBs never connect to AP WLAN services that are not compatible with the authorization or capabilities of a STA joining the WLAN using the WPS PCB process. However, this solution still does not prohibit STBs that are not customer identifier protected from pairing with lower priority or incorrect APs during the WPC PBC pairing process. The above disadvantages should be overcome and an easier and more secure method is needed to prevent undesired pairing of STAs with APs in a wireless network.